Thanks for the feedback, they will be either Samsung 830s or if the timing is right 840s. I am sorta leaning toward the zfs equivalent of raid 10 at this point. Do you guys see an issue using all of them in 1 pool/vdev in that scenario?
-----Original Message----- From: Roy Sigurd Karlsbakk [mailto:r...@karlsbakk.net] Sent: Monday, October 8, 2012 12:27 PM To: Discussion list for OpenIndiana Subject: Re: [OpenIndiana-discuss] Raid type selection for large # of ssds > I feel bad asking this question because I generally know what raid > type to pick. > > I am about to configure 24 256gig ssd drives in a ZFS/Comstar > deployment. This will serve as the datastore for a vmware deployment. > Does anyone know what raid level would be best. I know the workload > will determine alot, but obviously there is varying workload across a > vmware environment. Since we are talking about ssds I dont see a > particular reason to not create 1 big zfs pool, with the exception > that I know people generally try to keep the drive count from getting > out of control. Raid 10 seems like a waste of space with little > benefit in performance in this case. i am leaning towards raid z2 but > wanted to get everyones input. > > The datastore will host a fileserver, and exchange server for about 50 > users. The environment is all 10g and they have solid states in all > desktops so essentially that is the reason for such a large SSD > deployment for a small # of users. > > There seems to be varying opinions, especially when you factor in > trying to keep writes low for ssds. I can only share my experience with spinning rust. As others have said, I'd recommend against a single VDEV with all 24 drives. The chance of two or three dying at once is rather high with that number of drives. SSDs die too. A choice of 3x8 in RAIDz2 seems reasonable, or perhaps 2x7+1x8+spare (I know, it's uneven, but not that much, and a spare is a good thing). That'll give you IOPS comparable with 3x IOPS of a single drive, which should be pretty good with most SSDs. Also, keep in mind the problems with certain (or most?) SATA units connected to a SAS expander. I've seen pretty bad things happen with WD2001FASS drives in such a configuration (we had to replace about 160 drives and replace them with hitachis to solve that problem - not too much data was lost, though, thanks to pure luck). - What sort of SSDs are these btw? Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 98013356 r...@karlsbakk.net http://blogg.karlsbakk.net/ GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av idiomer med xenotyp etymologi. I de fleste tilfeller eksisterer adekvate og relevante synonymer på norsk. _______________________________________________ OpenIndiana-discuss mailing list OpenIndiana-discuss@openindiana.org http://openindiana.org/mailman/listinfo/openindiana-discuss _______________________________________________ OpenIndiana-discuss mailing list OpenIndiana-discuss@openindiana.org http://openindiana.org/mailman/listinfo/openindiana-discuss
